Nuclear Pulse Propulsion Re-Examined

byPaul GilsteronNovember 24, 2005

Consider two hypothetical spacecraft. The Orion vehicle would have worked by setting off low-yield nuclear devices behind a massive pusher plate, driving forward a payload attached at a safe distance from the pusher (and protected by mind-boggling shock absorbers). Even if we had the nuclear devices at our disposal, agreed to use them for such a purpose, and found the political will to construct an Orion craft for deep space exploration, a problem still remains: most of the energy from the nuclear blasts is dissipated into space, and the craft thus requires a huge critical mass of fission explosives.

Orion, in short, is not efficient in using its energies. Now consider Project Daedalus, the hypothetical mission to Barnard’s Star designed by members of the British Interplanetary Society back in the 1970s. Daedalus was designed to use fusion microexplosions instead of fission. One of the reasons the Daedalus craft demanded as much fuel as it did is that the ignition apparatus, whether laser or particle beam, to ignite fusion is massive, adding unwanted heft to the vehicle. Daedalus would have massed an overwhelming 54,000 tons.

But there is a third option, discussed by Friedwardt Winterberg (University of Nevada/Reno) in a new paper in Acta Astronautica. Winterberg describes so-called ‘mini-nukes,’ which are devices in which the mass of the fission explosive is hugely reduced by a reflector in which a deuterium-tritium (DT) fusion reaction takes place — the fusion neutrons thereby increase the fission rate, and the increased fission rate, in turn, increases the fusion production rate. The implosive compression to ignite the process is provided by chemical high explosives.

We wind up with a fission-fusion assembly with serious advantages: 1) we eliminate the weight of a laser or particle beam generator to ignite fusion, and 2) we add to the specific impulse and thrust of the exhaust, which is composed of combustion products both from the nuclear and chemical reactions.

And no longer do we, Orion-style, lose the bulk of our energies into space. “With mini-nukes,” Winterberg writes, “the situation is much better because the explosions can take place there in the focus of a parabolic reflector positioned in close proximity to the spacecraft. Since still smaller mini-nukes appear possible, with their feasibility depending only on the technical perfection to focus the chemical energy for ignition, the mini-nukes can be detonated inside a large combustion chamber…”

The paper is Winterberg, F., “Mini-fission-fusion explosive devices (mini-nukes) for nuclear pulse propulsion,” Acta Astronautica Vol. 57 (2005), pp. 707-712. Some of Winterberg’s earlier work was studied, incidentally, by the Daedalus designers as they set about examining various ways of making an inertial confinement fusion system that could power their starprobe.

And incidentally, check this Fusion News Update at the Star Spangled Cosmos site for news of a possible development in inertial confinement fusion in South Korea.

Creating an atomic explosion requires a maximium amount of 50 kg
of heu or 16 kg of Pu239 . It is not that difficult to make small nukes
massing 1000 kg or less for orion nuclear pulse units. This can however
best be achieved by using heu fueled nukes using the gun type trigger
system.
tim

Looking at the Web site listed above, it would seem that
Dr. Winterberg has gone a bit off the deep end – either
that or the Web site is one of those pseudoscience ones
that infest the Internet like a virus.

I have a deep mistrust of anyone who says that Einstein’s
physics ideas are flawed, not because I think old Albert was
infallible, but because the man has been proven right time
and again and every quack always seems to want to take
him down with their “absolutely right” Truth.

And being at a conference sponsored by Lyndon LaRouche –
that should be a red light and warning blare to anyone.

Karim, thank you for the link to the site on Friedwardt Winterberg. For those unfamiliar with the name, Winterberg’s work was consulted by the Project Daedalus team back in the early days of that JBIS project. In fact, he seems to have been a major source re a propulsion system that relied on pulsed fusion for the starship design. You can read more about his background at the site. I confess to having no prior knowledge of the Lyndon LaRouche event — curious!

To MirrorStephen:
In ancient time people believed that our Earth rests on three whales.
In 1650 archbishop Ussher declared about 7000 years of Universe existence.
Now you believe in Einstein’s pseudo theory of light waves flying upon
nothing.
But where is a causality?
Each physical wave is an oscillation (fluctuation) of environment.
Without environment, media, we can not say about any physical and any
logical model without contradictions.
Einstein’s theory states the nonexistence of ether, media of light waves.
There is a violation of causality and logic.
Einstein’s theory states about deflection of light near the Sun.
However there is no near other stars (for example, eclipsed binaries).
Einstein’s theory force logic by statement about mutual supremacy of both
twins ages.
In opinion of many true, non-speculative physicists keep an approach of
aetheReal physics ( see, for example, http://bourabai.narod.ru/ether.html )
Einstein’s physics is more politics and ideology than science.

I heartily congratulate everybody with the Day of Cosmotautics!
In April 12, Yuri Gagarin circumnavigated the globe in free Space.
He started from Kazakhstani cosmodrome Bay-Konur

Ah yes, the great Einstein Political Conspiracy, which all
physicist have apparently held to since 1905 at the least.

Do you happen to have a sample of this space aether
somewhere to prove your theory? Or, let me guess, you
did, but NASA has stealthed it away in some secret lab in
the Nevada desert and anyone who talks about it either
disappears or has an “accident”.

A “conference” sponsored by Lyndon LaRouche – if that doesn’t
smell of politics and the occult, I don’t know what does.

The critical advantage to the old fashioned fission concept is that fission devices are cheap and plentiful. The solution is just to launch a huge launch vehicle loaded with mass nuclear scrap. The environmentalists would go crazy but…

Actually, the Orion project proposed specially built 5 kT yield nuclear shaped charges which would have driven most of their energy at the pusherplate. The specific impulse and newtons would have been in the millions.

– “microlensing” is not gravitational phenomenon.
It is refraction of light in aether having different temperature, i.e. density.
I guess Andy has heard of light speed dependence from media density.
For more detailed explanation see “TEMPERATURE OF AETHER AND REDSHIFTS”http://bourabai.kz/redshifts-e.htm
and FAQ http://bourabai.kz/catechesis.html

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last eleven years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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